Trimming attachment for sewing-machines



(No Model.)

0. TIMM.

, TRIMMING ATTAOHMENT FOR SEWING MAGHINES. No. 452,556.

Patented May 19, 1891.

MW w M w? m UNITED STATES PATENT OFFICE.

CHARLES TIMM, OF MORGAN PARK, ASSIGNOR TO THE UNION SPECIAL SEWING MACHINE COMPANY, OF CHICAGO, ILLINOIS.

TRIMMING ATTACHMENT FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 452,556, dated May 19, 1891. Application filed February 2, 1891. Serial No. 379,912- (No model.)

To aZZ whom it may concern.-

Be it known that I, CHARLES TIMM, a citizen of the United States, residing at Morgan Park, in the county of Cook and State of Illinois, have invented anew and useful Improvement in Sewing-Machine Trimmer-Knives, of which the following is a specification.

In performing its function upon cloth while being sewed on a sewing-machine by cutting away the material close to the seam the trimmer knife, in its reciprocating movement through the slot commonly provided close to an edge of the throat-plate to admit the knife through it, tends to compact in the slot, and particularly behind the knife, fibers or lint freed from the cloth by the cutting operation.

Thus it quite frequently happens that a mass.

of such fibers will become so compactly wedged in the throat-plate slot as to cause the movements of the knife, in forcing its way past the mass it is at the same time further increasing and compacting, to break out the edge piece of the throat-plate forming one side of the trimmer-knife slot.- This obviously irreparably injures the throat-plate, necessitating its being supplanted by a new one, and besides, of course, it interrupts the operation of the machine, entailing inconvenience and annoyance.

The object of my improvement is to provide a construction of trimmer-blade for sewingmachines whereby it shall be adapted in its stroke to clear the throat-plate slot of the fibers or lint released from the material by cutting it and prevent its gathering and being compacted in the manner stated. To this end I form the blade with a desired number of teeth, preferably on the back edge of the blade, though they may be provided on one or both sides thereof or on one or both sides and the rear edge-thus, generically stated, on the blade behind the plane of its cuttingedge, whereby such tooth or teeth will in the stroke of the knife engage the loose fibers and carry them through the slot and thus maintain it clear, or comparatively so.

In the accompanying drawingsI show, by a perspective view, in Figure 1 a sewing-Inachine throat-plate with feed-dogs protruding through it and a trimmer-knife of my improved construction in position in a suitable trimmer-frame and protruding through its slot in the throat-plate. Fig. 2 is a view in elevation of my improved trimmer-knife detached.

A designates the throat plate, and B is a trimmer-frame supporting the knife O, which projects through the slot 0* and is operated to reciprocate through the slot by a common or any suitable mechanism, which forms no part of my present invention, and need not therefore be herein shown and described, being well-known to those skilled in the art to which my improvement relates. On the back of the blade (1 or the edge opposite the cutting-edge p, and on that portion thereof which comes in the movement of the knife within the plane of the slot 0, is a series of serrations o, the teeth being formed, preferably, to project outward and upward, and thereby adapted to perform the function stated in the manner described. One tooth 0 may in a measure answer the purpose. Hence I do not wish to limit the number to a series of the teeth, though such series is the more effective and desirable. Furthermore, the tooth or teeth may be arranged anywhere back of the plane of the cutting-edge of the knife and to extend in any desired direction or directions without thereby departing from the spirit of my invention.

What I claim as new, and desire to secure by Letters Patent, is-

1. In combination with the throat-plate of a sewing-machine, said throat-plate having a slot for the trimmer-knife, a trimmer-knife, and means for reciprocating it through the throat-plate slot, said knife having one or more teeth on the blade behind the plane of its cutting-edge, substantially as and for the purpose set forth.

2. In combination with the throat-plate of a sewing-machine, said throat-plate having a slot for the trimmer-knife, a trimmer-knife, and means for reciprocating it through the throat-plate slot, said knife having a series of upward and outward extending teeth 0 of teeth formed in the back edge of the blade,

formed in the back edge of the blade, subsubstantially as an (1 for the purpose set forth.

3. In combination with the throat-plate 0f stantiaily as and for the purpose set forth. a sewing-machine, said throat-plate having a 5 slot for the trimmer-knife, a trimmer-knife, In presence of and means for reciprocating it through the J. \V. DYRENFORTH, throat-plate slot, said knife having a series M. J. FROST.

CHARLES TIMM. 

